<template>
  <div>
    <!-- 评论列表 -->
    <van-list
      v-model="loading"
      :finished="commentsSum === 0 ? !finished : finished"
      finished-text="没有更多评论了，请发表评论"
      @load="onLoad"
      :immediate-check="false"
    >
      <div class="cmt-list" v-for="obj in commentsArr" :key="obj.com_id">
        <!-- 评论的 Item 项 -->
        <div class="cmt-item">
          <!-- 头部区域 -->
          <div class="cmt-header">
            <!-- 头部左侧 -->
            <div class="cmt-header-left">
              <img :src="obj.aut_photo" alt="" class="avatar" />
              <span class="uname">{{ obj.aut_name }}</span>
            </div>
            <!-- 头部右侧 -->
            <div class="cmt-header-right">
              <van-icon
                name="like"
                size="16"
                color="red"
                v-if="obj.is_liking"
                @click="isLike(true, obj)"
              />
              <van-icon
                name="like-o"
                size="16"
                color="gray"
                v-else
                @click="isLike(false, obj)"
              />
            </div>
          </div>
          <!-- 主体区域 -->
          <div class="cmt-body">
            {{ obj.content }}
          </div>
          <!-- 尾部区域 -->
          <div class="cmt-footer">{{ timeAgo(obj.pubdate) }}</div>
        </div>
      </div>
    </van-list>
    <!-- 评论区域  -->
    <div
      :class="{
        'art-cmt-container-1': inputState,
        'art-cmt-container-2': !inputState,
      }"
    >
      <!-- 底部添加评论区域 - 1 -->
      <div class="add-cmt-box van-hairline--top" v-if="inputState">
        <van-icon name="arrow-left" size="0.48rem" @click="$router.back()" />
        <div class="ipt-cmt-div" @click="inputBoxFn">发表评论</div>
        <div class="icon-box">
          <van-badge :content="commentsSum === 0 ? '' : commentsSum" max="99">
            <van-icon name="comment-o" size="0.53333334rem" @click="moveFn" />
          </van-badge>
          <van-icon name="star-o" size="0.53333334rem" />
          <van-icon name="share-o" size="0.53333334rem" />
        </div>
      </div>

      <!-- 底部添加评论区域 - 2 -->
      <div class="cmt-box van-hairline--top" v-else>
        <textarea
          placeholder="友善评论、理性发言、阳光心灵"
          v-focus
          @blur="unfocused"
          v-model.trim="comments"
        ></textarea>
        <van-button
          type="default"
          :disabled="comments.length === 0"
          @click="releaseFn"
          >发布</van-button
        >
      </div>
    </div>
  </div>
</template>

<script>
import { timeAgo } from '@/utils/date' //
import {
  discussCancelLikeApi,
  discussLikeApi,
  allArticlesDiscussApi,
  releaseDiscussApi
} from '@/api'
export default {
  data () {
    return {
      inputState: true, // 评论框显示
      commentsArr: [], // 评论数据
      commentsSum: 0, // 评论总数
      comments: '', // 评论内容
      loading: false, // 加载状态
      finished: false, // 全部加载完成
      offset: null // 文章偏移量
    }
  },
  async created () {
    const res = await allArticlesDiscussApi({
      type: 'a',
      source: this.$route.query.art_id
    })
    this.commentsArr = res.data.data.results
    this.commentsSum = res.data.data.total_count
    this.offset = res.data.data.last_id // 初始化评论偏移量
  },
  methods: {
    // 初始化时间
    timeAgo,

    // 点击 -> 是否点赞
    async isLike (bool, states) {
      if (bool === true) {
        // 取消点赞
        states.is_liking = !bool
        await discussCancelLikeApi({
          target: states.com_id
        })
      } else {
        // 点赞
        states.is_liking = !bool
        const res = await discussLikeApi({
          target: states.com_id
        })
        console.log(res)
      }
    },

    // 点击 -> 切换输入框
    inputBoxFn () {
      this.inputState = false
    },

    // 点击 -> 跳转到评论
    moveFn () {
      // 真实dom 都在document所以都能获取  scrollIntoView兼容性比较差 js原生兼容比较好(移动到当前获取的元素位置)
      document.querySelector('.like-box').scrollIntoView({
        behavior: 'smooth' // 定义动画过渡效果 默认 auto(没动画)
      })
    },

    // 评论框 -> 失去焦点 -> 延迟销毁评论框
    unfocused () {
      // 点击发布 失焦直接将评论标签移除太快导致评论还未发布 所以要用定时器延迟销毁
      setTimeout(() => {
        this.inputState = true
      }, 0)
    },

    // 点击 -> 发布评论
    async releaseFn () {
      const res = await releaseDiscussApi({
        target: this.$route.query.art_id,
        content: this.comments
      })
      this.comments = ''
      this.commentsArr.unshift(res.data.data.new_obj)
      this.commentsSum++
      this.moveFn() // 跳转到第一条评论
    },

    // 触底 -> 获取最新评论
    async onLoad () {
      if (this.commentsArr.length > 0) {
        const res = await allArticlesDiscussApi({
          type: 'a',
          source: this.$route.query.art_id,
          offset: this.offset
        })
        if (res.data.data.last_id === null) {
          this.finished = true
          return
        }
        this.offset = res.data.data.last_id
        this.commentsArr = [...this.commentsArr, ...res.data.data.results]
        this.loading = true
      }
    }
  }
}
</script>

<style scoped lang="less">
.cmt-list {
  padding: 10px;
  .cmt-item {
    padding: 15px 0;
    + .cmt-item {
      border-top: 1px solid #f8f8f8;
    }
    .cmt-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      .cmt-header-left {
        display: flex;
        align-items: center;
        .avatar {
          width: 40px;
          height: 40px;
          background-color: #f8f8f8;
          border-radius: 50%;
          margin-right: 15px;
        }
        .uname {
          font-size: 12px;
        }
      }
    }
    .cmt-body {
      font-size: 14px;
      line-height: 28px;
      text-indent: 2em;
      margin-top: 6px;
      word-break: break-all;
    }
    .cmt-footer {
      font-size: 12px;
      color: gray;
      margin-top: 10px;
    }
  }
}
/*美化 - 文章详情 - 底部的评论页面 */
// 外层容器
.art-cmt-container-1 {
  padding-bottom: 46px;
}
.art-cmt-container-2 {
  padding-bottom: 80px;
}

// 发布评论的盒子 - 1
.add-cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  box-sizing: border-box;
  background-color: white;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 46px;
  line-height: 46px;
  padding-left: 10px;
  .ipt-cmt-div {
    flex: 1;
    border: 1px solid #efefef;
    border-radius: 15px;
    height: 30px;
    font-size: 12px;
    line-height: 30px;
    padding-left: 15px;
    margin-left: 10px;
    background-color: #f8f8f8;
  }
  .icon-box {
    width: 40%;
    display: flex;
    justify-content: space-evenly;
    line-height: 0;
  }
}

.child {
  width: 20px;
  height: 20px;
  background: #f2f3f5;
}

// 发布评论的盒子 - 2
.cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 80px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  padding-left: 10px;
  box-sizing: border-box;
  background-color: white;
  textarea {
    flex: 1;
    height: 66%;
    border: 1px solid #efefef;
    background-color: #f8f8f8;
    resize: none;
    border-radius: 6px;
    padding: 5px;
  }
  .van-button {
    height: 100%;
    border: none;
  }
}
</style>
